Mumford et al. described the use of "Kevlar 49" in filament wound pressure vessels in a note from the AIAA/SAE/ASME 18th Joint Propulsion Conference, June 21-23, 1982, Cleveland, Ohio. For such application the filaments are ordinarily embedded in an epoxy resin matrix. Mumford et al. report that the fiber stress performance in the filament wound pressure vessel is lower than the nominal strand tensile strength. One way suggested in the article for utilization of a higher fraction of the fiber ultimate strength is coating the fiber with from 5 to 9% of a silicone release agent before application of the epoxy resin. This system has deficiencies and is not employed in polar windings of the pressure vessels. The present invention overcomes certain of these deficiencies and provides unusually high impact resistance to pressure vessels.